Questions tagged [8087]

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1answer
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Which x87 first acquired the ability to flush denormal to zero?

On modern Intel FPUs, you can set a flag to cause all denormals to be automatically flushed to zero. On some workloads, this improves performance. I cannot find any mention of that flag in the data ...
9
votes
1answer
841 views

What was the performance penalty for denormal inputs on 80s-era FPUs?

Some FPUs exhibit as much as an order of magnitude slowdown when given denormal inputs, due to having to trap to microcode to handle them. Did early FPUs of the microprocessor era, exhibit substantial ...
17
votes
3answers
2k views

x87 trigonometric instructions

The 8087 has instructions FPTAN and FPATAN, which are Partial Tangent and Partial Arctangent. The "partial" is presumably is to do with the range of the operands. For FPTAN the operand must be less ...